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		<H3><A name="HDRQANTIMG" ></A>QuantizeImage</H3>
		<P><STRONG>Category</STRONG>
		<P>
<A HREF="refgu008.htm#HDRCATTRN">Transformation</A>
<P><STRONG>Function</STRONG>
<P>Converts an RGB image to a byte image with a colormap
<P><STRONG>Syntax</STRONG>
<PRE>
<STRONG>images</STRONG> = QuantizeImage(<STRONG>Images, nColors</STRONG>);
</PRE>
<P><STRONG>Inputs</STRONG>
<BR>
<TABLE BORDER>
<TR>
<TH ALIGN="LEFT" VALIGN="TOP" WIDTH="20%">Name
</TH><TH ALIGN="LEFT" VALIGN="TOP" WIDTH="20%">Type
</TH><TH ALIGN="LEFT" VALIGN="TOP" WIDTH="20%">Default
</TH><TH ALIGN="LEFT" VALIGN="TOP" WIDTH="40%">Description
</TH></TR><TR>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH="20%"><TT><STRONG>images</STRONG></TT>
</TD><TD ALIGN="LEFT" VALIGN="TOP" WIDTH="20%">image, image series
</TD><TD ALIGN="LEFT" VALIGN="TOP" WIDTH="20%">(none)
</TD><TD ALIGN="LEFT" VALIGN="TOP" WIDTH="40%">image(s) to quantize
</TD></TR><TR>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH="20%"><TT><STRONG>nColors</STRONG></TT>
</TD><TD ALIGN="LEFT" VALIGN="TOP" WIDTH="20%">integer
</TD><TD ALIGN="LEFT" VALIGN="TOP" WIDTH="20%">256
</TD><TD ALIGN="LEFT" VALIGN="TOP" WIDTH="40%">maximum number of colors to use
</TD></TR></TABLE>
<P><STRONG>Outputs</STRONG>
<BR>
<TABLE BORDER>
<TR>
<TH ALIGN="LEFT" VALIGN="TOP" WIDTH="25%">Name
</TH><TH ALIGN="LEFT" VALIGN="TOP" WIDTH="25%">Type
</TH><TH ALIGN="LEFT" VALIGN="TOP" WIDTH="50%">Description
</TH></TR><TR>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH="25%"><TT><STRONG>images</STRONG></TT>
</TD><TD ALIGN="LEFT" VALIGN="TOP" WIDTH="25%">image, image series
</TD><TD ALIGN="LEFT" VALIGN="TOP" WIDTH="50%">resulting quantized image(s)
</TD></TR></TABLE>
<P><STRONG>Functional Details</STRONG>
<P>
QuantizeImage converts an image from a format in which the "colors"
component is a list of RGB (red, green, blue) vectors, with as
many entries as there are pixels in the image, to a format
in which the "colors" component is simply a list of unsigned bytes
which are interpreted as pointers into a color table.
<P>
QuantizeImage sets a "direct color map" attribute of 1 on its
output. When the output <TT><STRONG>images</STRONG></TT> is passed to
Display, this will force Display to use the colormap specified by
QuantizeImage, rather than a default colormap
(see <A HREF="refgu048.htm#HDRUDCMPS">"Using Direct Color Maps"</A>). This will
be the case even if you set the
environment variable DX8BITCMAP to 1. You can use the Options module to
set a "direct color map" attribute of 0 on the output of
QuantizeImage to force Display to use a shared colormap.
<TABLE CELLPADDING="3">
<TR VALIGN="TOP"><TD><P><B><TT><STRONG>images</STRONG></TT>
</B></TD><TD><P>is the image or series of images to be quantized.
</TD></TR><TR VALIGN="TOP"><TD><P><B><TT><STRONG>nColors</STRONG></TT>
</B></TD><TD><P>is the maximum number of entries in the color table.
</TD></TR></TABLE>
<P>
The output <TT><STRONG>images</STRONG></TT> will
be a new image or series of images in which
the color table is attached as a component called "color map".
<P>
The advantage of using QuantizeImage is that the image will consume
much less memory.
<P><STRONG>Components</STRONG>
<P>
Changes the "colors" component. Adds a "color map" component.
<P><STRONG>Example Visual Programs</STRONG>
<PRE>
SIMPLE/QuantizeImage.net
</PRE>
<P><STRONG>See Also</STRONG>
<P>
<A HREF="refgu118.htm#HDRRENDER">Render</A>,
<A HREF="refgu110.htm#HDRREADIMA">ReadImage</A>,
<A HREF="refgu173.htm#HDRWRITEIM">WriteImage</A>,
<A HREF="refgu048.htm#HDRDISPLAY">Display</A>,
<A HREF="refgu098.htm#HDROPTIONS">Options</A>
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